On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
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Página 50
... favourable to the genus ; and , conse- quently , we might have expected to have found in the larger genera , or those including many species , a large proportional number of dominant species . But so many causes tend to obscure this ...
... favourable to the genus ; and , conse- quently , we might have expected to have found in the larger genera , or those including many species , a large proportional number of dominant species . But so many causes tend to obscure this ...
Página 51
... favourable for variation ; and hence we might expect that the circumstances would generally be still favourable to variation . On the other hand , if we look at each species as a special act of creation , there is no apparent reason why ...
... favourable for variation ; and hence we might expect that the circumstances would generally be still favourable to variation . On the other hand , if we look at each species as a special act of creation , there is no apparent reason why ...
Página 60
... favourable to them during two or three following seasons . Still more striking is the evidence from our domestic animals of many kinds which have run wild in several parts of the world : if the statements of the rate of increase of slow ...
... favourable to them during two or three following seasons . Still more striking is the evidence from our domestic animals of many kinds which have run wild in several parts of the world : if the statements of the rate of increase of slow ...
Página 61
... favourable conditions , a whole district , let it be ever so large . The condor lays a couple of eggs and the ostrich a score , and yet in the same country the condor may be the more numerous of the two : the Fulmar petrel lays but one ...
... favourable conditions , a whole district , let it be ever so large . The condor lays a couple of eggs and the ostrich a score , and yet in the same country the condor may be the more numerous of the two : the Fulmar petrel lays but one ...
Página 64
... compete with our native plants nor resist destruction by our native animals . When a species , owing to highly favourable circum- stances , increases inordinately in numbers in a small tract 64 ON THE ORIGIN OF SPECIES.
... compete with our native plants nor resist destruction by our native animals . When a species , owing to highly favourable circum- stances , increases inordinately in numbers in a small tract 64 ON THE ORIGIN OF SPECIES.
Otras ediciones - Ver todas
On the Origin of Species by Means of Natural Selection: or the Preservation ... Charles Darwin Vista previa limitada - 2023 |
Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely